This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are studying the enzyme in the biosynthetic pathways of starch and inositol biosynthesis. To this end we are determining structures of the enzyme in these pathways. We have obtained diffraction quality crystals of MIP synthase from humans, pyrophosphoylase from potato tuber and branching enzyme from e. coli in a variety of forms. We will collect data and determine these structures and apply the structural information fo efforrts in rational enzyme design.